1. Technical Field
The disclosure relates to an endoscope.
2. Related Art
Conventionally, an endoscope has been known which is configured such that a soft and elongated insertion section is inserted into a subject such as a human to observe inside the subject (e.g., see JP 9-253035 A).
In an endoscope described in JP 9-253035 A, an insertion section includes a distal end body (hereinafter referred to as distal end member), and a bendable angle portion (hereinafter referred to as bending section) positioned on a proximal end side of the insertion portion relative to the distal end member (on a side separated from a distal end), and fixed to the distal end member. The insertion section includes a treatment tool insertion channel (hereinafter referred to as channel) through which various treatment tools are configured to be inserted.
The channel includes a treatment tool passage disposed in the distal end member, a cylindrical ferrule (hereinafter referred to as connection section) fitted into the treatment tool passage, and a tube disposed in the bending section and connected to the connection section. A treatment tool is inserted through the tube, and protrudes outward from the distal end of the insertion section through the connection section and the treatment tool passage.
However, in the endoscope described in JP 9-253035 A, the following situations may occur.
FIGS. 6A and 6B are diagrams illustrating situations of a channel 100 of the conventional endoscope. Specifically, FIG. 6A is a cross-sectional view of the conventional channel 100 when a connection section 200 is connected to a tube 300. FIG. 6B is a diagram illustrating a state of the connection section 200 and the tube 300 in the conventional channel 100 when the bending section is bent.
Specifically, the connection section 200 has an end portion 210 and the tube 300 has an inner surface, and while the cylindrical connection section 200 is fitted into the tube 300, the end portion 210 and the inner surface of the tube 300 do not form a continuous surface, and a step S appears between the end portion 210 and the inner surface of the tube 300 as illustrated in FIG. 6A.
As illustrated in FIG. 6B, when a treatment tool is used while the bending section is bent (bent upward in FIG. 6B), the treatment tool moves while making contact with the lower side of the inner surface of the tube 300 in FIG. 6B, and thus makes contact with the step S.
That is, unfortunately, the treatment tool is caught by the step S and causes abrasion of the inner surface of the tube 300, or the treatment tool makes contact with the step S and deterioration of the treatment tool occurs.
Therefore, there is a need to provide an endoscope which can reduce abrasion of an inner surface of a tube or deterioration of a treatment tool.